Organocatalytic direct aldol reaction between acetone and α-substituted β-keto esters

Gábor London, G. Szöllősi, M. Bartók

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The organocatalytic aldol reaction between acetone and α-substituted β-keto esters is presented. The α-unsubstituted or α-chloro ethyl acetoacetates failed to react with acetone when l-proline was used as catalyst. l-Proline or other optically pure pyrrolidine derivatives catalyzed the direct aldol reaction of acetone and α-fluorinated β-keto esters affording δ-keto-β-hydroxy-α-fluoro esters in high yields. Both the α-fluoro- and α,α-difluoro-β-keto esters functioned as aldol acceptors in these reactions. High ee values, up to 83% coupled with low diastereoselectivities were obtained in the reaction of ethyl 2-fluoroacetoacetate. Our study revealed a novel extension of the scope of the organocatalytic direct aldol reaction catalyzed by chiral organic bases, being the first report in which an asymmetric organocatalytic fluoroketone-ketone aldol addition has been described.

Original languageEnglish
Pages (from-to)98-101
Number of pages4
JournalJournal of Molecular Catalysis A: Chemical
Volume267
Issue number1-2
DOIs
Publication statusPublished - Apr 18 2007

Fingerprint

Acetone
acetone
esters
Esters
Proline
Ketones
ketones
Derivatives
Catalysts
3-hydroxybutanal
catalysts

Keywords

  • Acetone
  • Asymmetric
  • Direct aldol addition
  • Ethyl 2-fluoroacetoacetate
  • l-Proline

ASJC Scopus subject areas

  • Catalysis
  • Process Chemistry and Technology
  • Materials Science (miscellaneous)

Cite this

Organocatalytic direct aldol reaction between acetone and α-substituted β-keto esters. / London, Gábor; Szöllősi, G.; Bartók, M.

In: Journal of Molecular Catalysis A: Chemical, Vol. 267, No. 1-2, 18.04.2007, p. 98-101.

Research output: Contribution to journalArticle

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N2 - The organocatalytic aldol reaction between acetone and α-substituted β-keto esters is presented. The α-unsubstituted or α-chloro ethyl acetoacetates failed to react with acetone when l-proline was used as catalyst. l-Proline or other optically pure pyrrolidine derivatives catalyzed the direct aldol reaction of acetone and α-fluorinated β-keto esters affording δ-keto-β-hydroxy-α-fluoro esters in high yields. Both the α-fluoro- and α,α-difluoro-β-keto esters functioned as aldol acceptors in these reactions. High ee values, up to 83% coupled with low diastereoselectivities were obtained in the reaction of ethyl 2-fluoroacetoacetate. Our study revealed a novel extension of the scope of the organocatalytic direct aldol reaction catalyzed by chiral organic bases, being the first report in which an asymmetric organocatalytic fluoroketone-ketone aldol addition has been described.

AB - The organocatalytic aldol reaction between acetone and α-substituted β-keto esters is presented. The α-unsubstituted or α-chloro ethyl acetoacetates failed to react with acetone when l-proline was used as catalyst. l-Proline or other optically pure pyrrolidine derivatives catalyzed the direct aldol reaction of acetone and α-fluorinated β-keto esters affording δ-keto-β-hydroxy-α-fluoro esters in high yields. Both the α-fluoro- and α,α-difluoro-β-keto esters functioned as aldol acceptors in these reactions. High ee values, up to 83% coupled with low diastereoselectivities were obtained in the reaction of ethyl 2-fluoroacetoacetate. Our study revealed a novel extension of the scope of the organocatalytic direct aldol reaction catalyzed by chiral organic bases, being the first report in which an asymmetric organocatalytic fluoroketone-ketone aldol addition has been described.

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